1. Technical Field
This invention relates generally to methods and apparatus for forming a surgical opening, and more particularly to methods and apparatus for forming an opening into a bladder to provide access to the bladder, associated urological procedures and other surgical procedures.
2. Related Art
Bladder calculi (or stones) are common in the population and are presently treated either with open surgery through the abdomen, or transurethrally with the aid of a cystoscope and various fragmentation devices. Minimally invasive surgical therapy for kidney stones was started around thirty years ago, and adaptations of these techniques were applied to bladder calculi surgery just ten years ago. The same instruments used to treat kidney stones also work very well for bladder stones. The surgical challenge has always been to gain access to the bladder using a minimally invasive technique, and to prevent urethral trauma and later formation of urethral stricture (scar tissue).
Two widely-accepted techniques for creating percutaneous bladder access involve mechanical dilation, the most common of which is the “Amplatz” dilators and sheath. The second technique is the use of a special catheter with a balloon capable of enlarging openings percutaneously through the abdominal and bladder walls. Each is accomplished while a urologist observes transurethrally through a cystoscope the devices entering the bladder to be sure that, in the first case, that the Amplatz instruments do not perforate the rectum or vagina, and in the second case, the catheter location is indeed within the bladder instead of outside.
Transurethral bladder calculi treatment, though less invasive as open surgery, carries inherent risks to the patient. Repeated manipulation of instruments in the urethra during the procedure can create significant trauma. Transurethral bladder calculi treatment also can be expensive from the physician's standpoint due to the protracted time required to sufficiently break the stones to be passed through the urethra. The equipment required to break the stones transurethrally can also be expensive, as in the case of the Holmium:YAG laser.